Abstract
Despite their shared predilection for superficial soft tissue of distal extremities and frequent local recurrences, myxoinflammatory fibroblastic sarcoma (MIFS) and hemosiderotic fibrolipomatous tumor (HFLT) have distinct morphologic appearances. Recent studies have identified an identical t(1;10)(p22;q24) in 5 cases of MIFS and 2 of HFLT, as well as common amplifications on 3p11-12. In order to investigate further their potential relationship and to determine the incidence of t(1;10) in a larger cohort, we subjected 7 MIFS, 14 HFLT, and 3 cases with mixed morphology, to molecular and cytogenetic analysis. FISH analysis for rearrangements of
TGFBR3
on 1p22 and of
MGEA5
on 10q24 was performed in all cases, while the status of
VGLL3
gene amplification on 3p12.1 was investigated in 12 cases. Conventional karyotyping was performed in one HFLT and two cases with mixed MIFS/HFLT histology. Overall 83% of cases showed rearrangements in both
TGFBR3
and
MGEA5
. All three cases with mixed features of MIFS and HFLT were positive. Cytogenetic analysis performed in three cases confirmed an unbalanced der(10)t(1;10)(p22;q24).
VGLL3
gene amplification was noted in 10/12 cases of both histologies. The high incidence of t(1;10) in MIFS and HFLT reinforces a shared pathogenetic relationship. Furthermore, the co-existence of both components either synchronously or metachronously in a primary or subsequent recurrence, suggest either different morphologic variants or different levels of tumor progression of a single biologic entity. FISH analysis for
TGFBR3
and
MGEA5
rearrangements can be applied as a reliable diagnostic molecular test when confronted with limited material or a challenging diagnosis.
